Process of making coffee extract.



J. T. DAVIS. PROCESS OF MAKING COFFEE EXTRAGT. APPLICATION FILED IEB. 5, 1912.

1,079,474, PatentedNov. 25,1913.

H I 4 1'1!- (I WITNESSES i INVENTOR V I 25 hra/ wn I I, 24 I ATTORNEY I 55 across the vaporizer and p tures through Whichthe tubes 8 pass without UNITED. sra TEs G01, OF SAN FRANCISCO, CALIFORNIA,

.A CORPORATION 03 CALIFORNIA.

PROCESS OF MAKING COFFEE EXTRACT.

Specification of Letteu'latenti .Paten-tedhioy,25,1913.-

Applicatton fled February a, 18.12. iertalm 3 5.58.6-

To all whom it may concern Be it known that I, JOHN T. DAVIS, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State new and useful Improvements in Processes of Making Cofl'ee Extract, of which the following is a s ecification.

\ This invention relates to an improved process of making coffee extract, the object of the invention being to obtain such an extract free from the bitter and disagreeable essential oils of coffee which are driven off at the high temperatures usually employed in making such extracts.

v In the accompanying drawing, the figure is a vertical sectional, view of an apparatus for carrying out myimproved process.

Referring to conduit, having branches 2, by which pulverized roasted coffee is supplied by gravity to each of a series of infusing vessels 3. -Through said vessels in succession is slowly passed a stream of water at a tem erature of 165 F. or thereabout, the vesse s being maintained filled with the water by a properly regulated valve 40, the water at this temperature infusing the coffee and extract.

ing therefrom the more aromatic and agreeable oils. Af rleaving said series of vessels, the coffee in sion .flows by a pipe 4 "into the up er portion of a vaporizing chamber 5, pre erably of a cylindrlcal form,'having horizontal diaphragms 6, 7, near the top and bottom res ectively, said 'diaphragms being connected by a large number of. vertical open-ended tubes 8. Into the upper chamher 9, between the top of the vaporizer and the upper diaphragm 6, hot water flows, being conducted by a pipe 10 from a hot water tank 11, having a steam connection r12 for I maintaining hot the water in I said tank.

From the lower chamber .13, betweenthebottom of the vaporizer and the lower diaphragm, the water is conducted by a pipe 14 to a hot water H it is forced up a pipe 16' and back tothe hot water tank 11. The temperature of the hot water passing through the tubes 8 is main- 5 tained conslderably lower than boiling point, 165 F; being the preferred temperature. v a

' Ata short distance below the upper dia phragm 6 is a diaphra m- 17 extending ormed wlth aperof California, have invented.

the drawing, 1 indicates a pump 15, by which pump touching. Connected to the diaphragm 7 1s a discharge conduit 18 having a valve 19 therein, which conduit leads, to ,a tank 20, from the bottom of which tank leads a conduit; 21, having a valve 22 therein, and lea'dmg to a second tank 23 having a discharge outlet 24 and a valve 25 therein.

From the upper ortion of the chamber 26, between the iap ragms 17 and 7, a vapor pipe 27 leads to a' condenser 28, having above the entranceto said pipe 27 a-horizontal perforated diaphragm 29 for permitting cold water to pass through inthe form of a spray, which cold water is supplied from any suitable source. The water, after having performedits ofiice, flows from the condenser by a pipe 30, which pipe must be of a height of 32 feet, or thereabout, above its outlet, for the reason that the condenser is maintained under a more or less perfect vacuum, this result being effected by a pipe 31 leading to a vacuum pump 32.

The coffee berries, having been roasted, are-then pulverized, and an infusion is'made 30 therefrom in the manner already described. 7 This infusion is discharged into the chamber 5, and falls throu h the narrow annular openings in the diap ragm 17 around the tubes 8 and into the chamber 26. While so as falling, it is eva orated by the heat of the hot water in the tu 8, maintained at a comparatively low temperature, namely, 165 F. or thereabout, assisted by the more or less perfect vacuum produced by the suction gimp 32, causing the liquid coffee extract to 'concentrated. When it has been sulfic'ient ly concentrated, it is drawn into the receivin tanks 20, 23, in succession, two such tanks ing provided for. a eater convenience. Steam produced by t e evaporation is condensed by the cold water spray and is discharged at any suitable point.

a The value of this process consists in thefact that at no stage of the process, from the infusion of the pulverized coflee berries to the final-concentration of the extract, is the aroma of the coffee permitted to escape. It will be observed that the extractis compelled-to travel, from the beginning to the 105 end of the apgiiratus, in a conduit which is not open to t e atmosphere and is always maintained at less than atmospheric pressure.

claim:'v 1 The method i 11% of preparing coffee extract which consists in infusmg roasted pulver- 5 ture at less than atmospheric pressure.

2. The method of'preparing coffee extracts which consists in infusing roasted pulverized coffee berries with hot water at a tem- )GIflt-UIG of not more than 170 F., evaporatlo mg the Water therefrom by the application to.the mixture of heat at a temperature of not more than 170 F. and at all times, from the beginning to the end of said process, maintaining the coffee extract at a, pressure less than atmospheric. v

In testimony whereof I have hereunto set my hand in the presence of'two subscribing Witnesses.

j JOHN T. DAVIS Witnesses:

FRANCIS M. WRIGHT, D. B. RICHARDS. 

